若1/X - 1/Y＝3 求〔5X+2XY+5Y〕/〔X+4XY-Y〕的值

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x*x+y*y=x+y-1/2,求x,y的值如题 y=(2x*x-2x+3)/(x*x-x+1),求值域? 若x-y=3,x^2-y^2=1,求x+y的值 4x-3y=5 x^2+y^2=1 求x,y 3x+4y-5=0 x^2+y^2=1求x.y x+y=8 2x-y=1 求3x+5y 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) 若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式 x+y分之x-y+x-y分之x+y 已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值 若1/X - 1/Y＝3 求〔5X+2XY+5Y〕/〔X+4XY-Y〕的值 求y=(5x-1)/(4x+2) (x y=(X+1)(X+2)(X+3)求导数 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y